/*
 * Created on 6 May 2008
 * Created by Allan Crooks
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package org.gudy.azureus2.plugins.config;

import java.io.File;

import org.gudy.azureus2.plugins.Plugin;
import org.gudy.azureus2.plugins.PluginConfig;
import org.gudy.azureus2.plugins.PluginInterface;

/**
 * This interface provides a mechanism for plugins to store configuration settings in a separate configuration file (rather than the main Azureus
 * configuration file).
 * 
 * <p>
 * 
 * <b>Important:</b> If you are using this class for a plugin which previously used to store configuration settings in the main configuration file
 * (which is what most existing plugins do), you should call the {@link #forceSettingsMigration()} method to get existing settings moved over - please
 * read the comments for that file if you need to do that.
 * 
 * <p>
 * 
 * To create an instance of this file, you need to call {@link PluginConfig#enableExternalConfigSource()}. Once you have an instance, you then need to
 * call {@link #initialize()} to configure it - though there are additional methods that you can call for additional configuration.
 * 
 * <p>
 * <b>Note:</b> Only for implementation by Azureus, not plugins.
 * </p>
 */
public interface PluginConfigSource {

    /**
     * This initializes this configuration object and gets the external configuration file integrated with Azureus.
     * 
     * <p>
     * 
     * It performs the following steps:
     * <ul>
     * <li>Loads the data of any existing config file into Azureus.
     * <li>Registers all parameters in the file to be stored inside this configuration file (so all changes will be stored here).
     * <li>Adds a hook to allow it to be automatically saved when Azureus autosaves its own internal configuration files.
     * <li>Adds a hook to intercept any configuration settings created and used by the plugin and stores it internally (rather than being saved in the
     * main Azureus config file).
     * </ul>
     */
    public void initialize();

    /**
     * This method sets the filename for the configuration file that this object links to - this must be done before the {@link #initialize()} method
     * is called.
     * 
     * @param filename
     *            The filename to use.
     */
    public void setConfigFilename(String filename);

    /**
     * Returns a file object which represents the location of the configuration file that this object interacts with.
     */
    public File getConfigFile();

    /**
     * Manually saves the configuration settings recorded by this object to disk. This isn't normally required, as Azureus will automatically save the
     * configuration file when the main configuration file is saved, but you can choose to save on demand if you wish.
     * 
     * <p>
     * 
     * @param force
     *            <tt>true</tt> if you want the file to be written to regardless of whether there are any changes, <tt>false</tt> if you only want to
     *            save the file if there are unsaved changes.
     */
    public void save(boolean force);

    /**
     * If your plugin previously used to store data in the main configuration file, you can call this method (which needs to be done soon after
     * initialization) which will move all monitored parameters over to this object.
     * 
     * <p>
     * 
     * You have to call this method before you initialize the object. It's also recommended that if you call this method, that you call
     * {@link #save(boolean)} to save any settings copied across - probably best to be done as the last thing of the
     * {@link Plugin#initialize(PluginInterface)} method.
     */
    public void forceSettingsMigration();
}
